TL;DR: I want to give my brother some money with a few conditions on how it is spent but believe he is unlikely to realise that I seriously plan to enforce those conditions. How can I convey my seriousness to him?
I have an older brother whom I do/have gotten along well with for all of my life but is not so great with money/self control. Nothing so bad as having a gambling addiction, series of maxed out credit cards or anything of that sort, but as a particularly careful saver the difference made from his buying nice clothes, a modest car, a nice tv/speaker system, semi-regularly eating out and maintaining an enthusiastic social life is very clear. Obviously I have no problem with him or anyone buying these things, it is a personal decision of my own not to.
When I was 16 and he was 18 we both still lived with our parents and despite earning more than me, he would often ask to borrow small amounts of money. $20 here, $50 there and it accumulated to ~$500 before I started refusing to lend any more as it was a lot of money for me at the time. After two years of occasional nagging it was clear that I would never get that money back so I offered to forgive the loan if his old laptop I had been using for the past couple months (he paid $250 for it new) could be "mine" and that was the end of it. That is not to say I have never owed him. While studying at the university, I knew that whenever desperate I could sleep on the couch at his place and eat his food, use the shower, internet, get dropped off at a train station and he would not expect anything in return. And there were a fair number of times where I did exactly that.
Nowadays we each semi-regularly give/borrow/loan small amounts of money from each other but just recently he has mentioned in a more significant sense how he is running out of money and might have to borrow some from me. He recently lost his primary source of income and although there is no worry about his residency or physical health and well-being, the extra money for things like car maintenance, job searching, bills, general quality of life costs and the ability to buy things that will help in the long term would clearly be a massive help to him. Since I am aware of a number of these sorts of things coming up soon that are in his own best interest to buy, I am more than happy to give him up to $1000 which if he can return then great but I half expect, and am fully prepared, to never see that money again. However, he has bad spending habits and receiving enough money does not mean that he will buy these things that he needs. Based off my knowledge of his self control and past dealings with money I have no doubt that if I just gave him all the money he would carry on buying excessive items and then suddenly realise that he only bought half of the things he actually needed. I am happy to pay for his fuel, but not a $60 haircut and round of drinks for his friends. So when I do give him the money, I want to establish some strong conditions about what I am giving it to him for. When it is his own money, I am happy for him to spend it how he likes but since this is my own money, I feel it is similarly fair to spend it how I want.
After some thought the essential steps would be to:
Separate the amount I give him into sections to limit the carelessness at which it can be spent.
Tell him what the money is for, and establish a boundary that if it is spent on other things I will not give any more money.
Follow through
Limit yes, but I am not prepared to only give minuscule amounts at a time or demand receipts/be asked and present for every purchase, that is far more of a strain on his time, my time and our relationship than I think its worth. Although I won't (and don't want to) know his specific purchases, if he were to for example spend the money going to a concert instead of fixing his car, both of these sorts of things I will know about anyway and can confidently use to enforce said rule. I do not want to be involved to the extent where I am basically be his financial arbiter and he would not want that either. The general understanding I already have of what he buys is more than enough since when it gets to the point where he has to ask, he would be well and truly out of money and I can be confident that 95% of what he buys would come from my money. 1 & 3 are self explanatory and do not think I will not have trouble with following through and enforcing my boundary. My question is about skills or techniques that can be used to express that I am absolutely serious when I initially talk to him in step 2.
For some context. There are a number of other issues that were expressed in a similar way, but we BOTH clearly acknowledge as not being serious. There are plenty of examples of this going both ways, from situations like "If there is so much as a scratch on my car I won't let you drive it to {$Best Friend}'s wedding." To things as trivial as "You aren't invited to dinner if you eat that last muffin." These cases are all empty threats and we both know it. Since using the car was known as the only feasible option left to travel to the wedding, and we both recognised it as something significant giving this over the top, false ultimatum was a way to express how much I didn't want it to be scratched and nothing more. If it had been scratched although I may have gotten mad, I am confident my brother would not have even have to ask to know that it was still fine to use the car when he needed. The muffin comment was a competitive joke, I immediately ate it in the face of his protests and yet there was no question about the validity of my invite.
So my worry is that even if I say "I will not give you any more money if you spend it on X" he may presume that I am just expressing that I don't want him to spend it on X rather than establishing a solid boundary of something that will actually happen. If I am able to properly convey to him how serious I am about the condition it will be vastly better for the both of us by helping with his spending, my peace of mind knowing what the money is going to and in the case where I actually do have to enforce the boundary at least he will be expecting it.
Asking for money is awkward and I assume he will try to finish the conversation as fast as humanly possible so a lengthy conversation about my thoughts may not work in this case...
What conversational skills and techniques can I use to quickly and effectively convey to my brother that I am setting a firm boundary rather than just expressing my hopes?